Or more simply, Jazzaria is about freedom, and the music here is as free as
feasible. For original work, you can listen to, download, and reuse/remix (even
commercially) the music you find here. For example, you can use music here as
a soundtrack for your own projects, or sample it for your own music, and release
your work either freely or commercially. The only requirements are to attribute
Jazzaria as your source and use a similar license for your work. An example of
proper attribution:

(Description of what material you used and potentially how it was altered) was
originally created by Jazzaria.com, and is reused here
under a CC BY-SA 4.0
license.

To choose a compatible license (satisfying the SA clause), see the Creative
Commons essay on
understanding Free Cultural Works.
The easiest thing to do is just pick the same license used here (CC BY-SA), but
you can also use the straight attribution license (CC BY) or dedicate your work
to the public domain (CC0).

For work that is a “cover”, it is not possible to give it freely and so instead
it is made available for purchase through standard channels. Original work will
also be available through these channels, and additionally can be purchased at
lossless quality (FLAC) and with the
option of reuse without the SA clause (licensed CC BY). Other outlets may also
sell more commercial (competely non-CC) licenses for reuse.

Aside from the above usage rights, Jazzaria maintains full copyright on all
material. If you wish to obtain more detailed aspects of the work (e.g.
tracks/“stems”, notation, MIDI data, etc.), reuse commercially without
attribution, or commission custom work, then you can contact Jazzaria through
the “Feedback” link available on the side of the front page.